night mission

I still consider myself very much a novice on my road bike. Dealing with a compact crank, I have accidentally found myself crossed chained more often than I'd rather admit. So to better know whats going on (below and behind) me, I often find myself looking back to see what cog I'm in. I'm getting better at shifting and sensing where I am and (more importantly) where I need to be. Still just curious, how confident are you in knowing where you are on your crank and cog? Cadence and (perceived) speed are my (only?) tools at this point. Do others have advice on gear management and knowing the difference between a 12 and a 13, and more to the point, is it important??

fietsbob

I know for Me , You have to figure out if its important For you, Yourself,


Gearing is a series of Gear ratios like 2:1 you tun the pedals once the wheel turns twice

Gear inches is taking that 2 and multiplying it by the wheel diameter, in Inches obviously..

work out the Math and you can write a chart so you know whats next.. in the ratio sequence..

another way often used . development .. circumference of wheel x gear ratio ,

that is how far you go over the ground for each crank rotation, that is typically stated in Meters.


With an IGH the sequence of ratios is sorted out by the manufacturer 1.2.3.4. etc. each a % of the other..

you pick where the range falls , by the external cog sizes .. another ratio choice ..

Sheldon Brown's Bicycle Gear Calculator

slimyfrog

This site has many nerdy calculators, such as:
BikeCalc.com - Bicycle Gear Ratio Chart
or
BikeCalc.com - Speed at all Cadences for any Gear and Wheel

calamarichris

Which drivetrain are you running? One reason (one of the many) I like Dura Ace 7800 is the available gear indicator on the shift cable.
I suppose someone could mount this on a 7900 or 9000, but haven't tried it on my gf's bike.
The next simplest gear indicator is downtube shifters.



Someone on Google put them on a mountainbike, so I suppose it's possible.

Drew Eckhardt 

Shift cogs as needed.

When it ceases to run silently due to cross-chaining, switch rings and make a compensating rear shift.

Intuitively you should figure out what works. Otherwise you can use arithmetic.

For instance, cruising along in 39x13 you don't like the noise from the chainline.

13/39 * 50 yields 16.67 so 39x13 is like 50x17.

With cogs that run 13-14-15-16-17 that's a 4 cog change. If you planned to up-shift because your legs are speeding up a 3-cog move to 50x16 would be better. Front and rear mechanisms can be shifted simultaneously, with a chain catcher making that nearly 100% reliable moving to small ring and smaller cog.

If it's quiet it usually doesn't matter.

You don't need to care about specific cogs unless you're considering changing them at which point you want to know what you're missing and willing to give up. For instance, if you're switching back and forth between 17 which is too hard and 19 which is too easy too easy you might want one tooth jumps through the 19. If you rarely use your smallest cog you might start your next cassette one tooth bigger to gain the 18.

hueyhoolihan

most people, IMO, have little idea what actual gear they are in. there're too many and too close together for that.

now guys with 3-speed IGHs probably know. and i used to know when i owned a five speed with one chainring.

night mission

Good Advice


Thinking about gear ratios while cruising , "How many yards will i travel with 39x13, and what was the equivalent on the large chain ring???..........." Time might be better spent looking for potholes or hope I'm far enough to the right so that tire noise that's getting louder will hopefully pass safely.

practical

I ride a triple 9 speed flat bar bike with gear indicators and a compact double 10-speed with brifters and no indicators. I love having indicators and I have a system for shifting gears. I am never certain with the bike without indicators.

Retro Grouch 

I think that many posters make the whole shifting process much more complicated than it needs to be. With 7 or more rear cogs the steps between gears are always manageable. Just think of your bike as having 2 or 3 gear ranges: One for up hills and one or two for everything else.

CliffordK

Most modern gearing systems are fairly tolerant of cross chaining.

I do look behind me every once in a while. With downtube or stem shifters on a couple of bikes, it is easier as I can just look at or feel the relative shifter positions.

I do have a bad habit of dropping the front on a hill, then forgetting to shift it back up when I get to the top. A few miles down the road, I start wondering why slowing down.

Jim from Boston

Being "One " with your bikes (gearing)

I use cadance and Relative Perceived Exertion (RPE) (see below) to choose gears. For flat to rolling hills I am usually in the larger front cog to maintain a cadence of 90, at an RPE of 60%, and shift the rear cluster to maintain. As my cadence rises, I shift up (or vice versa). For intervals, done on hills, I ride at 70% RPE, and maintain a cadence of about 60 to 80, and shift to the smaller front cog as needed.

I suppose the more data-driven cognoscenti might use heart rate monitors or power meters. Of course for just recreational riding, it just might be whatever feels good.

See also this concurrent thread on the General Cycling Discussion Forum, ”Just how many gears are enough for a bike”

bakes1

Out of curiosity, why do you think you ever need to know what gear you are in?
If based upon the road condition and your ability you are pedaling efficiently, it makes no difference.
I would be surprised if you are cross chaining for no other reason than not knowing exactly what gear you are in.
Either way, cross chaining once in awhile is no big deal.

OldsCOOL

POn my main road warrior I find myself instinctively knowing the gear just by the needed pedal pressure and mph. When on a long, tiring ride I may just stay on the small ring of the 53/39 too keep things simple.

When riding one of the classics in the fleet for just a casual ride, I will glance at the rear cog more frequently.

Retro Grouch 

That's what I think too. If it's too hard to pedal, shift into an easier gear. If you think that your feet are spinning too fast, shift into a harder gear.

ltxi

I have Tiagra shifters with gear indicator windows. After a couple hundred miles (I'm a slow learner) I don't pay much attention to them. Don't need to no more. Keep riding, you'll get there. As to cross chaining....I do it intentionally at times. Like when I know I'm only going to need that higher gear for a light load short bit.